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Søren Ulstrup

Kinks in the σ Band of Graphene Induced by Electron-Phonon Coupling

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  • Federico Mazzola, Norwegian University of Science and Technology, Norway
  • Justin Wells, University of Science and Technology, Norway
  • Rosita Yakimova, Linköping University, Sweden
  • Søren Ulstrup
  • Jill Miwa
  • Richard Balog
  • Marco Bianchi
  • Mats Leandersson, Lund University, Sweden
  • Johan Adell, Lund University, Sweden
  • Philip Hofmann
  • T. Balasubramanian, Lund University, Sweden
Angle-resolved photoemission spectroscopy reveals pronounced kinks in the dispersion of the band
of graphene. Such kinks are usually caused by the combination of a strong electron-boson interaction and
the cutoff in the Fermi-Dirac distribution. They are therefore not expected for the band of graphene that
has a binding energy of more than 3:5 eV. We argue that the observed kinks are indeed caused by the
electron-phonon interaction, but the role of the Fermi-Dirac distribution cutoff is assumed by a cutoff in
the density of states. The existence of the effect suggests a very weak coupling of holes in the band
not only to the electrons of graphene but also to the substrate electronic states. This is confirmed by the
presence of such kinks for graphene on several different substrates that all show a strong coupling constant
of 1.
Original languageEnglish
JournalPhysical Review Letters
Publication statusPublished - 21 Nov 2013

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